Most of this change is fixing up the numerious tests that violated this rule.
Fixed: tint:1365
Issue: tint:1374
Change-Id: I38da27c7367277fe60857208170fec017e80bd25
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/76400
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Remove the ICE check for expression behaviors always being either `{Next}` or `{Next, Discard}`. Unreachable code may be result in something else.
Add the RemoveUnreachableStatements transform to the SPIR-V writer sanitizer transform list. The writer cannot correctly handle unreachable statements.
Bug: tint:1369
Bug: chromium:1285622
Change-Id: I9fa54c6d2096b1ee633dd551b628c7dd3ba64fb5
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/76300
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
All failures are now SKIP'ed.
Bug: tint:1358
Change-Id: If04d57b9e0b71dd877468b5dc277fbff82f36692
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/75220
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
Constructing a null vector, matrix or array does not need to provide an explicit list of null elements. `T()` is a more efficient and readable equivalent.
Fuzzers like to generate enormous pathological composite types, which has been triggering OOM failures.
Bug: oss-fuzz:38095
Bug: oss-fuzz:39235
Bug: oss-fuzz:39246
Bug: oss-fuzz:39874
Change-Id: I910bb04bdd0e80532c09fc038be895ec37d3d380
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/75426
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Just like for divide, FXC fails with the exact same error when
performing a modulo on a value that FXC determines to be zero. We
address it in the same way as we do for divide.
This also fixes a couple of the vk-gl-cts tests for which I manually
generated expectation files for.
Bug: tint:1083
Change-Id: Ia388bf002112afded542adb791d37e88e35a77ff
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/74220
Reviewed-by: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
FXC fails to compile when it determines that the rhs of an integral
division is zero with "error X4010: Unsigned integer divide by zero".
bclayton's fix (https://dawn-review.googlesource.com/c/tint/+/60500)
addressed cases for division by an integer constant 0. This CL adds the
missing support for division by integral vectors with 0 components.
FXC also fails on division by integral expressions that it can fold to
0. To handle these cases, we now emit a runtime check for 0 and replace
by 1. In the cases I've tested, FXC seems able to optimize these checks
away.
Bug: tint:1083
Change-Id: I02f08e9077882f03c1e42b62dacb742a48fa48ba
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/73580
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Change-Id: I32aaefe71ea728ae5118de08e5dd9073ddf2269e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/73740
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
FXC fails to compile code that assigns to dynamically-indexed fixed-size
arrays in structs on internal shader variables with:
error X3500: array reference cannot be used as an l-value; not natively
addressable
This CL detects this case, and transforms such assignments into copying
out the array to a local variable, assigning to that local, and then
copying the array back.
Also manually regenerate SKIPs for HLSL/FXC after this change, which
fixes 30 tests. Also exposes some "compilation aborted unexpectedly" now
that "array reference cannot be used as an l-value" has been fixed. For
tests that fail for both DXC and FXC, updating SKIPs to the DXC one to
help distinguish actual FXC bugs from valid errors.
Bug: tint:998
Bug: tint:1206
Change-Id: I09204d8d81ab27d1c257538ad702414ccc386543
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/71620
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
The GLSL emitted for these was invalid, and we don't need these
structs since they're only used as the store types of buffers, which
are handled elsewhere.
Change-Id: I17c15e408b5c36e9b895e5950528a6d02d1802a6
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/72381
Reviewed-by: Stephen White <senorblanco@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
This has been deprecated and will soon be removed.
Bug: tint:1324
Change-Id: If5dbbc3a40d7591591fb2802dbe9c8dd5f96d299
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/72087
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
These are no longer necessary and will soon be deprecated and removed.
Bug: tint:1324
Change-Id: I3fa076e7ce5eb36466d24c80fd1c83658c28c5ab
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/72086
Reviewed-by: David Neto <dneto@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Skipping those that are block-decorated is not correct, as
block-decorated structures can also have non-buffer usages. This is
even clearer now that WGSL has removed the block attribute.
Bug: tint:1324
Change-Id: I6484766a5c541d39e2dc08beb3ae7b889759a3fb
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/72083
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
It seems we haven't run our e2e tests with FXC validation in a long time
- at least not since we've added the vk-gl-cts corpus.
Locally disabled exclusion of "/test/vk-gl-cts/" in test-runner/main.go,
and ran:
./test/test-all.sh out/build/x64-Debug/tint.exe --format hlsl --fxc --generate-skip
These will need to be manually removed once the skips aren't needed by
deleting them all, and re-running as above.
Bug: tint:940
Change-Id: I27e395e69f5e1bd7d234f3155f40396b751720d4
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/71981
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
This new expectation file was added with a similar parent that changed the expected output.
Bug: tint:1112
Change-Id: Icb6175f68b6459385933d39e07460eb863ecb9ff
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/71101
Commit-Queue: Ben Clayton <bclayton@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Now that I've landed this change to Dawn to disable FXC optimizations:
https://dawn-review.googlesource.com/c/dawn/+/70700,, we can reland this
change. The Tint-into-Dawn roll was failing because FXC would miscompile
certain loops into infinite loops when not unrolled.
Also reland
test/bug/fxc/gradient_in_varying_loop/1112.wgsl.expected.hlsl
Bug: tint:1112
Bug: dawn:1203
Change-Id: I641d68864b833e0fbe3b117d397b89ae96482536
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/71000
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
It's surprising that the fuzzers didn't find this, but I've confirmed that at least one of the fuzzers will fail with this case.
By adding a e2e test case, this will be used as a seed for the fuzzer corpus.
Bug: tint:1321
Change-Id: Ibf4bfa50bf376ae4cba401dfc31a2498fa3b9eec
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/70982
Reviewed-by: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Add transform::Unshadow to renamed shadowed symbols. Required by a
number of other transforms.
Replace Resolver symbol resolution with dep-graph.
The dependency graph now performs full symbol resolution before the
regular resolver pass.
Make use of this instead of duplicating the effort.
Simplfies code, and actually performs variable shadowing consistently.
Fixed: tint:819
Bug: tint:1266
Change-Id: I595d1812aebe1d79d2d32e724ff90de36e74cf4b
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/70523
Reviewed-by: David Neto <dneto@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
This reverts commit 11d09f2fe7.
Reason for revert: Failing roll of Tint to Dawn: https://dawn-review.googlesource.com/c/dawn/+/70100
Original change's description:
> HLSL: force FXC to never unroll loops
>
> Emit the "[loop]" attribute on "for" and "while" so that FXC does not
> attempt to unroll them. This is to work around an FXC bug where it fails
> to unroll loops with gradient operations.
>
> FXC ostensibly unrolls such loops because gradient operations require
> uniform control flow, and loops that have varying iterations may
> possibly not be uniform. Tint will eventually validate that control flow
> is indeed uniform, so forcing FXC to avoid unrolling in these cases
> should be fine.
>
> Bug: tint:1112
> Change-Id: I10077f8b62fbbb230a0003f3864c75a8fe0e1d18
> Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/69880
> Kokoro: Kokoro <noreply+kokoro@google.com>
> Reviewed-by: Ben Clayton <bclayton@google.com>
> Commit-Queue: Antonio Maiorano <amaiorano@google.com>
# Not skipping CQ checks because original CL landed > 1 day ago.
Bug: tint:1112
Change-Id: I8e8f3c0abfa6e6bc5d0e67af9428a46ef867d5c1
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/70540
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
No need for the HLSL-style repeated swizzle; GLSL allows construction
of a vector from a scalar value of the component type.
Bug: tint:1317
Change-Id: Ia0afe3012cbb56716a2d1c5c3849dd662a5ff89c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/70342
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
Use imageSize() on images, not textureSize().
In GLSL, the LOD parameter to textureSize() is mandatory for
sampled textures, so emit a default 0 if not supplied. (Also, don't pack
the level into the coords argument; that's an HLSLism.)
GLSL returns the array size of array textures in the final component
of textureSize(); remove it for WGSL.
Write the subtype of storage images correctly (uimage*, iimage*, etc).
This required a bit of cleanup to move "writeonly" ahead of subtype
emission.
Bug: tint:1298
Change-Id: Ica1cec0f833a9b684143c8b0cf6d090fb511a7d2
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/70140
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Emit the "[loop]" attribute on "for" and "while" so that FXC does not
attempt to unroll them. This is to work around an FXC bug where it fails
to unroll loops with gradient operations.
FXC ostensibly unrolls such loops because gradient operations require
uniform control flow, and loops that have varying iterations may
possibly not be uniform. Tint will eventually validate that control flow
is indeed uniform, so forcing FXC to avoid unrolling in these cases
should be fine.
Bug: tint:1112
Change-Id: I10077f8b62fbbb230a0003f3864c75a8fe0e1d18
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/69880
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Use uintBitsToFloat.
Bug: tint:1306
Change-Id: Ie9a5e14c13c0d63b57c126f16c4e2a5c7a77e3f7
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/69740
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
In GLSL, all identifiers beginning with gl_ are reserved (not just those
explicitly named in the spec), and so any found in WGSL must be renamed.
Bug: tint:1304
Change-Id: I92ed7ec674620f67775378ecb8debcfdb4b5bbb4
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/69701
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
In GLSL, relational operators are only valid for scalar operands. For
vector operands, lessThan, greaterThan, etc must be used.
Bug: tint:1303
Change-Id: Ia800f89111630c756dc1b30ef0c6858fb520fb16
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/69561
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
To fix this, we trick the compiler by wrapping the function body with an
if (true) { <function body> } followed by returning an unused value of
the return type.
Bug: tint:1081
Change-Id: I763bf768f40d07a1045f0a70017bb40d488c8428
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/68822
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Some pass DXC, but not FXC (e.g. continue_in_switch).
Some now pass (e.g intrinsics/gen/atan2/*.hlsl)
Some now fail gracefully instead of asserting (e.g. 807.spv)
Change-Id: I92b17fcadc7850de5bd93ff07507cea7e5487fc9
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/68820
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@chromium.org>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
The semantic nodes cannot be fully immutable, as they contain cyclic
references. Remove Resolver::CreateSemanticNodes(), and instead
construct and mutate the semantic nodes in the single traversal pass.
Give up on trying to maintain the 'authored' type names (aliased names).
These are a nightmare to maintain, and provided limited use.
Significantly simplfies the Resolver, and allows us to generate more
semantic to semantic references, reducing sem -> ast -> sem hops.
Note: This change introduces constant value propagation across constant
variables. This is unlocked by the earlier construction of the
sem::Variable.
Change-Id: I592092fdc47fe24d30e512952511c9ab7c16d7a1
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/68406
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Update or remove tests that try to do this.
Fixed: tint:491
Change-Id: I1f351a4abf68ae9bc6b100885fb1bcea08b31211
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/68242
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
WGSL does not support pointer-to-vector-component, so the SPIR-V
reader needs to sink these pointers into their use.
Bug: tint:491
Change-Id: Ib5ae87d2f6bbac13280314ba11369d7ced505b56
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/68241
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
This removes a lot of awkward logic from the MSL writer, and means
that we now handle all module-scope variables with the same transform.
Change-Id: I782e36a4b88dafbc3f8364f7caa7f95c6ae3f5f1
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/67643
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
The `Ignore()` intrinsic is about to be deprecated, so don't use it for testing.
Bug: tint:1213
Change-Id: I314ecaeb9a9c337c7b6980189054120a74807ebd
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/67066
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>
Reviewed-by: James Price <jrprice@google.com>
Metal 1.x does not support swizzling on packed_vec types.
Use array-index for single element selection (permitted on LHS and RHS of assignment)
Cast the packed_vec to a vec for multiple element swizzles (not permitted as the LHS of an assignment).
Fixed: tint:1249
Change-Id: I70cbb0c22a935b06b3905d24484bdc2edfb95fc2
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/67060
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>
The intrinsics that did anything useful with this were deprecated
several releases ago.
Change-Id: I79e3c901b6a78583853a067ec46cfa98e346517c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/66262
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>
Update one test to avoid this error.
Fixed: tint:1179
Change-Id: Id41b0eb0f404648de4e86a835fe43f1729cb4696
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/64464
Auto-Submit: David Neto <dneto@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: David Neto <dneto@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Change ast::Array to use an ast::Expression for its `size` field. The
WGSL frontend now parses the array size as an `primary_expression`,
and the Resolver is responsible for validating the expression is a
signed or unsigned integer, and either a literal or a non-overridable
module-scope constant.
The Resolver evaluates the constant value of the size expression, and
so the resolved sem::Array type still has a constant size as before.
Fixed: tint:1068
Fixed: tint:1117
Change-Id: Icfa141482ea1e47ea8c21a25e9eb48221f176e9a
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/63061
Auto-Submit: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
In https://dawn-review.googlesource.com/c/tint/+/62444 the Resolver validated that there are no parameters of the same function with the same name, but this also introduced validation that errors if parameters shadow a module-scope variable.
The WGSL spec allows for shadowing, but Tint so far has not implemented this support.
There are transforms that generate functions that presume parameter <-> module-scope variable shadowing is okay. DecomposeMemoryAccess is one of these.
This fixes those transforms which could generate programs that fail validation.
Bug: chromium:1242330
Fixed: tint:1136
Change-Id: Id6ec59bbdb398b3b2a23312115a7c1dadf433e98
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/62900
Reviewed-by: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
These operators are not defined in the metal namespace when the vector
operands are packed.
Fixed: tint:1121
Change-Id: I2e8f4302e08117ca41bac6c05fb24a70d1215740
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/62480
Kokoro: Kokoro <noreply+kokoro@google.com>
Auto-Submit: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
MSL vectors with other widths already match WGSL's rules for alignment
and size.
Change-Id: I237052372463ea8323eab47c3b4ca90c6d8afcc3
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/62600
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Remap all resources into a flat namespace, to allow tests to pass when
multiple resources use the same binding number.
Fixed: tint:959
Change-Id: I58ed07c789e1ea90fc370ceba73b9d8292902549
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/61261
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
This new test was added around the same time as the entry point IO
rework, so the (now incorrect) test output made it past the bots.
Change-Id: I89fc4041b9cd00cd363ba61d07371554263eca96
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/61460
Auto-Submit: James Price <jrprice@google.com>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: James Price <jrprice@google.com>
SPIR-V spec states:
> Each structure-type member that is a matrix or array-of-matrices must have be decorated with a MatrixStride Decoration
As already pointed out in https://dawn-review.googlesource.com/c/tint/+/59840, we were not handling arrays-of-matrices.
To do this correctly, we need the ast::StrideDecoration to be placed on the Matrix type, which is a much bigger change to support.
For now, chase the type, and error if we have a custom MatrixStride on an array of matrices, otherwise drop the decoration.
Bug: tint:1049
Fixed: tint:1088
Change-Id: Idcb75b3df88040836a03a14e0ca402ebee7be9a7
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/60923
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: David Neto <dneto@google.com>
Auto-Submit: Ben Clayton <bclayton@google.com>
The refactored CanonicalizeEntryPointIO transform makes it much easier
to handle SPIR-V style IO as well, and doing this removes a lot of
duplicated code. Remove all of the SPIR-V transform code for shader IO
and vertex point size.
Bug: tint:920
Change-Id: Id1b97517619b4d2fd09b45d5aee848259f3dfa77
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/60840
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: James Price <jrprice@google.com>
Auto-Submit: James Price <jrprice@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>